The speed and density of computation have been doubling every three years (at the beginning of the twentieth century) to one year (at the end of the twentieth century), regardless of the type of hardware used.... Despite many decades of progress since the first calculating equipment was used in the 1890 census, it was not until the mid-1960s that this phenomenon was even noticed (although Alan Turing had an inkling of it in 1950).

The Age of Spiritual Machines: When Computers Exceed Human Intelligence (2000)